Chucking mechanism



July 15, 1941, w. L. GROENE CHUCKING MECHANISM Filed Feb. 15, 1940 2 Sheets-Sheet l INVENT OR.

July 15,1941. w. 1.. GRQENE 2,249,243

CHUGKING MECHANI SM 2 Sheets-Sheet 2 Filed Feb. 15, 1940 Patented July 15, 1941 UNITED STATES PATENT OFFICE Y CHUCKING MECHANISM Willard L. Groene, Cincinnati, Ohio; assignor to The R. K. LeBlond Machine Tool Company, Cincinnati, Ohio, a corportion of Delaware 'Application February 15, 1940,.Serial No. 319,051

IiClaims. gotta-t).

This invention pertains to the chucking of rough irregular preloc'atedwork pieces in a machine tool. More particularly this'invention is adapted to initially support a prelocated work piece in a lathe which is to be gripped by a chuck-f ing device by means of rough irregular surfaces on said work piece. i

For illustrative purposes this invention is shown applied specifically to the chucking of a crankshaft in a double center drive crankshaft lathe for the purpose of having the various line bearings machined on said crankshaft.

An object of this invention is to provide a work supporting device which supports a rough irregular work piece accurately on its prelocated position on the axis of rotation of the lathe and holds said work rigid during the application of chuck ing devices which engage rough irregular portions of said work piece. It is then the object to remove this initial supportingdevice after the work piece has been properly chucked so that the cut-j continue the machining operting tools may then ation on the crankshaft. I I

More specifically, an object of this invention is to provide in a center drive lathe, a means for initially supporting a rough irregular work piece on its prelocated axis in the lathe and then to apply the chucking devices of the center drive work spindles to the work piece while it is being held by this initial supporting device so that these the work rigidly and posi-' chucks may engage tively without distorting the work during the chucking operation. It is then the purpose to remove this initial holding or supporting device to the work piece so as to permit the crankshaft to be further machined by the cutting tools of the lathe. I

This invention overcomes one of the mostdifli cult problems of chucking a rough irregular work piece which has been prelocated in a lathe. It is a well known fact that when grippingsuch a rough irregular prelocated work piece the chucking device must have equalizing mechanism which permits the chuck to engage the work without distorting it from its true axis of rotation while at the same time these devices-must have abilty to rigidly hold the work during the cutting operation of the cutting tools on the surfaces of the work.

impossible heretofore to provide such chucking devices which were sufficiently free in equalizing movement to permit gripping the work without distorting it from its true prelocated position while at the same timeproviding sufiicient rig- It is well known that in such an arrangement it is idity for-the chucking devices when holding the work during the cutting operation.

It'is therefore the chiefobject of this invention to provide a device which will rigidly supportthe-work while such-chucking devices are initally clamping and gripping the work so that these devices maybe made with their equalizing'mechanism sufiiciently rigid and resistant to movement to hold the work rigidly during the cutting operation while at the same time providing this unique device for holding the work rigidly during the initial chuckingoperation so that these relatively rigid equalizing members do not distort the work from its true prelocated position in the lathe.

Further features and advantages of this invention will appear from the detailed description of the drawings in which: Figure I is an end elevation, partly in section On 1ine'I'I of Figure II, of 'a portion of a double center'drivecrankshaft lathe having chucking devices for gripping a rough irregular work piece and showing this uniquepre-supporting device for the work piece in position on the frame of 1 the. lathe associated with the center drive rough work engaging chucking device.

' Figure II is a front elevation of a portion of the double center drive lathe shown in Figure I. Figure III is a section through the dovetail sliding :mounting for the pre-supporting device shown on. the line III-III of Figure I;

For illustrative purposes this invention. is

shown applied to a typical double center drive crankshaft lathe'of a character shown in Patent No. 2,069,107 dated Jan. 26, 1937, having the center drive ring gear housings I and 2 and the tailstocks 3 and 4. appropriately mounted on the frame of the lathe. In each of the tailstocks 3 and which contain suitable chucking mechanisms in- V dicated generally at 9 for gripping rough irregular'w'ebs I0 and I l of the crankshaft 6 after it has been appropriately placed and thereby prelocated onthe center 5 of the lathe. Such a chucking device, for example, may be of a character as shown in application Serial No. 299,560 filed Oct. 14, 1939.- v

in the frame of. the lathe;

In conjunction with these centers 5 and the chucking devices 9 it is the object to provide an additional movable supporting device for the center line bearings I2 of the crankshaft 6 to support this bearing accurately without springing the shaft from its true prelocated position on the centers 5 of the lathe prior and during the eneasement Of h chuc in devices 8 on t e webs I and II of the crankshaft. After having thus chucked the shaft by means of the webs I0 and II this center line bearing supporting device is then to be removed from work engaging position to allow access of the various cutting tools! to machine the line bearing portions of the erankshaft. This initial supporting device for the center line bearing comprises a bracket I3 which is securely bolted to the center drive ring gear and by suitable screws I4 and has formedit a dovetail guideway I5 in which nicely slides the work supportin member I6. This work supporting member 16 has abifurcated end portion hav-- ing the prongs I60, and ISb in-which are nicely fitted the'knurled set screws II. In the crotch of this bifurcated end portion is also provided a suitable fixed abutment screw I8. Through the slotted portion I9 of the work supporting meme ber I6 projects a clamp stud 2,0 fixed in the bracket I3 and having a nut and washer -2-I which may be drawn down tightly against the face I60 of the work supporting member I16, for locking this member against the sliding movement in the guideways I5 and therebylocking it securely to the center drive ring gear housing I.

The operation of this chucking mechanism is substantially as follows:

The crankshaft 6 is first placed through the center drive ring gear housings I and 2 and mounted on the centers'5. of the tailstocks 3 and 4 as is customary for lathes of this Next, the work engaging member I6 which hasup to this time been moved back to the withdrawnlposi-u tion shown at Hid is now moved downwardly hav-. ing loosened the nut ZI until its abutment screw I8 nicely engages the rough bearing surface of the line bearing I2. The not and washer 2| are then looked down tight rigidly clamping this work engaging member I6 to the ,centerdrive ring gear housing I. The knurled set screws IT- arev then lightly screwed down against this hearing I2. The crankshaft is therefore locked rigidly at its center against any possible movement .or distore tion from its true axially located position effected by the centers 5, at the ends of the shaft. The chucking devices in the center drive b.0115: ings I and 2 are then operated to grip the webs I0 and II ,of the crankshaft firmly, and in so, doing they do not distort the crankshaft or spring it from its. true prelocated axial position because of the rigid support provided by the work engag-.. ing member I6. As soon as the chuck has prop-, erly engaged the webs Illand II, the knurled set screws I! are then loosened and the nut 2I also. loosened and the work engaging member I6 is slid back'to withdrawn position and the lathe is then in condition for operation of the cutting tools, upon the work piece. I-Iavingscompleted theturning operation on these line bearings L, the chucking devices. in thecenter drive housings Iv and 2 are then. released and they work with.- drawn from the centers 5 in the usual manner.

In thisway, the crankshaftis chuckedrigidly'and firm y by m ans of. t r uehirr su ar s rfaces with precision, strength and ri idi y t prevent: true prelocated positi n. as. tools operating upon the its. distortion from its caused by the cutting work and at the same time the mechanism I6 prevents any distortion occurring in the shaft during the initial chucking operation which would otherwise take place if equalizing chucking devices having sufficient rigidity to hold the work during the roughing turning operation on the crankshaft.

I-Ia ving thusv fully set forth and described my invention what I claim as due and desire to secure by United States Letters Patent is:

1. In a lathe, means for prelocating a rough irregular work piece on the axis of rotation of said Lathe, means engaging said work piece for initially supporting said Work piece rigidly when positioned by said .prelocating means, and chucking mechanism adapted to grip said prelocated work piece by rough irregular surfaces thereon while being held rigidly by said initial supporting means, and means for withdrawing said initial supporting means from engagement with the wo k a ter aidc u k na m c an sm hasbeen ul y eng ed on sai work piece.

n. a. d ub e 'cent r. ir e'1ath a pair of cente s, io s ppo t ns t e e ds of a workp ece. n e ca ed n siti nl nse d a he, a work hold- 111% memb a ed. n rme ate said centers adapted to rigidly hold said work piece in said pr ocated it on, c u kin m chan m l ated in ermedia e said cent s adap to enga esaid w r piece by m ans of rough. r u ar surfaces of sai w r pi e while sa d w rk h ldinsmemr ber is effectively rigidly holding said work piece in said prelocated position, and means for withdr i a d Wo k h ld n mem r. a ter said. ch i g m h nism. has u iy eng ecd said work. P 69 3. In a double center drive crankshaft lathe, a frame, tailstocks mounted on said frame, centers i aid ia sfio v eans, r ag said centers in the ends o a c anksh ft to b ma hined sa d a he to t by prepositio said crankshaft in axial alignment in saidlathe a work support: ing member, movable into engagement, with said q z n shaf er edi e ts en ca r n th frame of said lathe, a pair of center drive ring ea chuck de ou ted ach side .of said. w k sup o t g mem er huck ng; ,de i es, in each of said ring gears adaptedto chu k said crankshafts. by mean-sot rough irregular surfaces. thereon, means for engaging said work support ing m mb on the work p e ur s id hucking operation of said chucking devices on said wor iec and me s o herawi-ng saidwork, su por in 'memb r f m said work p e e afterd huc ing de e ave e n en age on; s d wor p ec Y r 4. In a center drive crankshaft lathe, a frame, a, pair, of tailstocks mounted on each end of said frame, c te in said ail ccksr s or ene. ga ing id e ers tben lsoi the. wo k piece o, be ma ined sa lathe to. preposition said q k; n e e a ia a ignment in said lathe; a, center driye, chuckin device mounted inter-- mediate said centers, chucking mechanism in said c nter drive chuckingdeviceadapted to gri said work piecehy meansof rough irregular surfaces he eon, an. initial: work; supporting devic asso.-.

iated' with said; chucking :device carried on. the frame o a df-Qr'moy ng said chuck n iievice 1 1120.. engagement with said work piece bri iit all held: saidiwcrk piec during the.

ch31. k ns of: said; work Piece by. said chucking dense: nd: means er: wi hdraw n sa d. .wo fls;

supporting: member to withdr wn. pcsition; when ing said chucking device has been fully engaged on said work piece.

5. In a lathe, means for prelocating a work piece on the axis of rotation of said lathe, a chucking device in said lathe adapted to grip said work piece, means associated with said chucking device adapted to initially rigidly hold said work piece accurately on said axis during the application of said chucking device to said work piece, and means for withdrawing said initial holding means after said chucking device has been engaged on said work piece. I

6. In a lathe, means for prelocating a rough irregular work piece on the axis of rotation of said lathe, an equalizing chucking device adapted to engage and hold said work piece for rotating it by means of rough irregular work surfaces of said work piece, and means for initially rigidly holding said work piece in said prelocated position during the ing device to said work piece, said means withdrawing from'said work piece when said chuckevice is fully engaged on said work piece.

'7. In a double center drive crankshaft lathe,

a pair of tailstocks, centers in said tailstocks adapted to engage the ends of a crankshaft to be machined in said lathe to position it in prelocated position on the axis of rotation of said lathe, a pair of center drive housings, a center drive ring gear in each of said housings, equalizing chucking devices in each of said ring gears, adapted to engage rough irregular crankshaft for chucking and rotating it during the cutting action of cutting tools on bearing portions of said crankshaft, a work supporting member located between said center drive housing adapted to be moved into engagement with said work piece to rigidly hold said work piece during the application of said chucking devices on said work piece, and means for moving said work engaging member out of work engaging position after said chucking devices have been gripped on said work piece.

8. In a double centetr drive crankshaft lathe,

a pair of tailstocks, centers in said tailstocks adapted to engage the ends of a crankshaft to be machined in said lathe to position it in prelocated position on the axis of rotation of said lathe, a pair of center drive housings, a center drive ring gear in each of said housings, equalizing chucking devices in each of said ring gears, adapted to engage rough irregular webs of said crankshaft for chucking and rotating'it during the cutting action of cutting tools on bearing portions of said crankshaft, a work supporting member located between said center drive housings adapted to be moved into engagement with said work piece to rigidly hold said work piece during the application of said chucking devices on said work piece.

9. In a double center drive crankshaft lathe, a pair of tailstocks, centers in said tailstocks adapted to engage the ends of a crankshaft to prelocate it on the axis of rotation of said lathe, a pair of center drive chuck housings, a pair of ring gears rotatably mounted in said housings,

equalizing chucking mechanism in each of said ring gears adapted to engage said crankshaft by means of rough irregular webs thereof, an initial work supporting device center drive ring gear housings, means for movapplication of said equalizing chuckmounted on one of said webs of said ing said device into engagement with a rough line bearing of said crankshaft is rigidly supported against distortion from its true axial prelocated position in said lathe, and means for applying said equalizing chucking devices to said work piece While said work piece is so held by said work engaging member, and means for moving said work engaging member from engagement with said rough line bearings after said chucking device has-engaged the rough irregular webs of said crankshaft.

10. In a double center drive crankshaft lathe, a pair of tailstocks, centers in said tailstocks adapted to engage the ends of a crankshaft to be machined in said lathe, a pair of center drive housings located intermediate said centers, rotary ring gears mounted in said housings, equalizing chucking devices in each of said ring gears adapted to engage rough irregular Webs of said crankshaft, an initial supporting device for said crankshaft, effective during the chucking of said crankshaft by said chucking devices, comprising a member movable into engagement with said crankshaft intermediate said centers, means for locking said member in engagement with one of the ring gear housings of said lathe for rigidly supporting said crankshaft during the clamping of said chucking devices on said crankshaft.

11. In a lathe, means for prelocating a work piece on the axis of rotation of said lathe, means for initially rigidly holding said work piece intermediate its ends in said prelocated position, means for chucking said crankshaft while so supported, and means for withdrawing said initial holding means after said chucking mechanism has been engaged on said'work piece.

12. In a crankshaft lathe, a new article of manufacture, comprising a prelocating device for use in holding a crankshaft in a predetermined aligned position without deflection while chucking devices are being applied, said new article of manufacture comprising a detachably supported arm on a crankshaft chuck, and means on said arm for engaging a crankshaft and adjustably positioning it in aligned position while it is being chucked.

13. In a crankshaft lathe, means comprising a support at either end of a crankshaft, maintaining it in aligned position and permitting its rotation in such position, a crankshaft chuck having means for engaging said crankshaft to hold it in aligned position and rotate it, and means mounted on said chuck comprising prealigning means for engaging said crankshaft to hold it in position while it is being chucked to prevent distortion of the crankshaft out of its aligned position while being so chucked.

14. In a crankshaft lathe, a chuck comprising means for engaging a bearing portion of a crankshaft to hold said crankshaft in predetermined axial position with respect to the center of the chuck, an additional means for engaging crankshaft web engaging a bearing portion of said crankshaft to hold them in predetermined alignment being detachable from said crankshaft after said crankshaft has been chucked in said lathe. I

' WILLARD L. GROENE.

crankshaft whereby said portions in order to chuck and rotate said crankshaft in said lathe, said means for 

